docs

tests/fixtures/mcp_echo_server.py

@@ -9,6 +9,7 @@ from pydantic import Field
 
 
 server = FastMCP("echo-fixture")
+_remembered_value: str | None = None
 
 
 class EchoToolResult(TypedDict):
@@ -22,6 +23,22 @@ async def echo_tool(
     return {"echoed": text}
 
 
+@server.tool(title="Remember value tool")
+async def remember_value_tool(
+    value: Annotated[str, Field(description="Value held in this server process.")],
+) -> dict[str, str]:
+    """Store state so proxy tests can distinguish reused and fresh sessions."""
+    global _remembered_value
+    _remembered_value = value
+    return {"remembered": value}
+
+
+@server.tool(title="Recall value tool")
+async def recall_value_tool() -> dict[str, str | None]:
+    """Return process-local state written by `remember_value_tool`."""
+    return {"remembered": _remembered_value}
+
+
 @server.tool(title="Resource link tool")
 async def resource_link_tool() -> list[mcp_types.ResourceLink]:
     """Return a link to a fixture resource so proxy URI rewriting is testable."""

tests/wf_mcp/test_protocol_relay.py

@@ -70,7 +70,7 @@ def test_fixture_server_emits_observable_protocol_notifications_directly() -> No
     assert "notifications/message" in methods
 
 
-def test_proxy_does_not_relay_upstream_protocol_notifications_yet() -> None:
+def _fixture_proxy_notification_methods() -> list[str]:
     config = BrokerConfig(
         store_root=local_temp_root() / "protocol_relay_store",
         connections=[
@@ -102,5 +102,29 @@ def test_proxy_does_not_relay_upstream_protocol_notifications_yet() -> None:
     except PermissionError as exc:
         pytest.skip(f"stdio MCP transport is not permitted in this environment: {exc}")
 
-    methods = _notification_methods(notifications)
-    assert methods == []
+    return _notification_methods(notifications)
+
+
+def test_proxy_does_not_relay_generic_upstream_notifications_yet() -> None:
+    methods = _fixture_proxy_notification_methods()
+
+    # Stateful proxy sessions preserve FastMCP's supported request callbacks,
+    # but generic upstream change/update notification rebroadcast is separate
+    # protocol relay work.
+    assert "notifications/tools/list_changed" not in methods
+    assert "notifications/resources/list_changed" not in methods
+    assert "notifications/prompts/list_changed" not in methods
+    assert "notifications/resources/updated" not in methods
+
+
+@pytest.mark.xfail(
+    strict=True,
+    reason=(
+        "FastMCP StatefulProxyClient log forwarding assumes mapping-valued log "
+        "data; valid string-valued MCP logging data is rejected upstream."
+    ),
+)
+def test_proxy_relays_string_valued_upstream_log_when_fastmcp_supports_it() -> None:
+    methods = _fixture_proxy_notification_methods()
+
+    assert "notifications/message" in methods

tests/wf_mcp/test_proxy.py

@@ -83,14 +83,16 @@ def test_proxy_lists_and_calls_upstream_tools() -> None:
             proxy_tools_payload = _structured(proxy_tools_result)
             proxy_tools = proxy_tools_payload["tools"]
             assert proxy_tools_payload["nextCursor"] is None
-            assert proxy_tools_payload["total"] == 3
-            assert len(proxy_tools) == 3
+            assert proxy_tools_payload["total"] == 5
+            assert len(proxy_tools) == 5
             assert proxy_tools[0]["proxy_name"] == "fixture.personal.echo_tool"
             assert proxy_tools[0]["connection_id"] == "fixture.personal"
             assert proxy_tools[0]["local_name"] == "echo_tool"
             assert proxy_tools[0]["enabled"] is True
             proxy_names = [tool["proxy_name"] for tool in proxy_tools]
             assert "fixture.personal.emit_notifications_tool" in proxy_names
+            assert "fixture.personal.remember_value_tool" in proxy_names
+            assert "fixture.personal.recall_value_tool" in proxy_names
             assert "fixture.personal.resource_link_tool" in proxy_names
 
             proxy_tool_result = await client.call_tool(
@@ -153,6 +155,39 @@ def test_proxy_rewrites_resource_links_returned_by_tools() -> None:
     asyncio.run(run_proxy())
 
 
+def test_proxy_reuses_one_upstream_session_for_stateful_tools() -> None:
+    """Visible proxy tools must share server-local state for one MCP client."""
+    config = BrokerConfig(
+        store_root=local_temp_root() / "proxy_stateful_session_store",
+        connections=[
+            ConnectionConfig(
+                id="fixture.personal",
+                server="fixture",
+                account="personal",
+                metadata={
+                    "transport": "stdio",
+                    "command": sys.executable,
+                    "args": [fixture_server_path()],
+                },
+            )
+        ],
+    )
+
+    async def run_proxy() -> None:
+        client = create_proxy_client(config)
+        async with client:
+            written = await client.call_tool(
+                "fixture.personal.remember_value_tool",
+                {"value": "held"},
+            )
+            recalled = await client.call_tool("fixture.personal.recall_value_tool")
+
+            assert _structured(written)["remembered"] == "held"
+            assert _structured(recalled)["remembered"] == "held"
+
+    asyncio.run(run_proxy())
+
+
 def test_proxy_rejects_invalid_connection_config() -> None:
     config = BrokerConfig(
         store_root=local_temp_root() / "proxy_invalid_store",
@@ -355,7 +390,7 @@ def test_proxy_proxy_tool_listing_supports_filters_and_cursor() -> None:
             first_page = _structured(first_page_result)
             assert len(first_page["tools"]) == 1
             assert first_page["nextCursor"] is not None
-            assert first_page["total"] == 6
+            assert first_page["total"] == 10
 
             second_page_result = await client.call_tool(
                 "wf.admin.list_proxy_tools",